The woman said she had been left unable to sleep or concentrate on daily tasks, resulting in her taking time off work.
And she had also suffered panic attacks in public when she saw anyone who resembled Tapata.
"Bronson has ... no mana," she said.
Counsel Sonia Vidal pointed to a psychologist's report which highlighted her client's remorse and said he presented a low risk of reoffending.
Judge Rollo said the two sexual acts, which made up the charges, happened four months apart and represented a severe breach of trust.
Tapata had known the girl when she was an infant and had children of his own who were a similar age.
"The circumstances have brought about great sadness and great upset and feelings of depression for the young girl involved," he said.
"You were the adult, it was your responsibility to recognise the road this young girl was prepared to embark on was wrong."
Tapata had at least made admissions to police and been open with his whanau. The court heard they were initially "distressed and disturbed" but had opted to rally around him.
He will serve the home-detention sentence with his parents in Invercargill.
Judge Rollo said anyone who had experienced lockdown would appreciate what an arduous sentence that was.
Tapata was also sentenced to 150 hours' community work and ordered to pay the victim $1500 within a month.
He was barred from contact with under-16s for the duration of his sentence, except for family members, while in the presence of a responsible adult.
The judge opted against adding Tapata to the Child Sex Offender Register.
SEXUAL HARM - DO YOU NEED HELP?
If it's an emergency and you feel that you or someone else is at risk, call 111.
If you've ever experienced sexual assault or abuse and need to talk to someone contact Safe to Talk confidentially:
• Call 0800 044 334
• Text 4334
• Email support@safetotalk.nz
• For more info or to web chat visit www.safetotalk.nz
Alternatively contact your local police station - click here for a list.
If you have been abused, remember it's not your fault.